Low-growing ground-covers can fill empty space around a Japanese yew. Choices include sulphur flower (Eriogonum umbellatum ), a North American native that grows up to 12 inches tall and 3 feet wide. Hardy in USDA zones 4 through 8, this perennial ground-cover blooms in summer, producing aromatic, yellow flowers that attract butterflies. Sulphur flower performs best in a sunny, well-draining site. If you want ground-cover with year-round foliage, then bearberry (Arctostaphylos uva-ursi "Big Bear") is an option. The evergreen plant grows 6 to 12 inches tall and 3 to 6 feet wide, forming a carpet of shiny foliage that takes on a red tinge in winter. Bearberry displays white-pink flowers in spring followed by red berries. It's hardy in USDA zones 2 through 7 and grows well in a sunny, dry site.
Ornamental grasses offer vertical interest and color, and they add a rustling sound to the landscape with every passing breeze. Japanese yew companion ornamental grasses include blue grama (Bouteloua gracilis), a 2-foot-tall grass that thrives in a sunny, dry location. The North American native has red-purple flowers in summer, and its blue-green foliage turns purple in fall. Blue grama grass is hardy in USDA zones 3 through 10. Another possibility is "Golden Toupee" fescue (Festuca glauca "Golden Toupee"), which provides a splash of bright, yellow-green coloring. A small, drought-tolerant cultivar of blue fescue, this grass grows 6- to 9-inch-tall clumps of fine, chartreuse foliage and is hardy in USDA zones 4 through 7. "Golden Toupee" performs best in sunny and dry to medium-dry conditions.
If you prefer color through the growing season, plant perennials that flower at different times. Sea thrift (Armeria maritima) blooms with showy, pink and white flowers in spring. This 6- to 12-inch-tall perennial is hardy in USDA zones 4 through 8 and grows best in a sunny, dry spot. For summer blossoms, plant snow-in-summer (Cerastium tomentosum), a 6- to 12-inch-tall perennial hardy in USDA zones 3 through 7. The sun-loving plant produces white flowers that offset yew's dark foliage. Goldenrod (Solidago speciosa) produces yellow flowers from July through September. Hardy in USDA zones 3 through 8, the North American native grows to 2 to 3 feet tall and thrives in full sun.
Plant sun-loving annuals near your Japanese yew for even more color. Choices include cosmos (Cosmos sulphureus), a versatile annual that grows up to 6 feet tall and produces brilliant-yellow blossoms. Cosmos thrives in a sunny site and tolerates dry soil. Plains coreopsis (Coreopsis tinctoria) provides more bright color. This 2- to 4-foot-tall annual blooms from late spring through fall and attracts butterflies; each of its flowers has golden, daisylike petals around a red-brown center. Coreopsis performs best in a spot with full-sun exposure and well-draining soil.